PTK2 and lung cancer: Paxillin regulates ERK signaling at focal adhesions through other kinases such as Focal Adhesion Kinase (Ishibe et al., 2004). Paxillin—MEK-ERK complex serves as a regulator of HGF-stimulated FAK and Rac activation in the focal adhesions, thereby regulating tumor cell invasion, plasticity, and metastasis (Deakin et al., 2012). Paxillin is over-expressed in lung adenocarcinoma high-risk patients. Mutations in Paxillin have been associated with enhanced tumor growth and invasion in lung cancer (Mackinnon et al., 2011).